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Compress a PDF on a Mac

A Mac can make a PDF smaller in two ways. Preview's Reduce File Size filter is built in and takes one click. The compress tool in Safari, Chrome or Firefox takes a size you type, such as 200 KB or 2 MB, keeps the text selectable, and checks the result before you download it. Both run on the Mac, so the document stays with you.

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How to compress a PDF on a Mac

  1. Check the size

    Select the PDF in Finder and press Command and I. Get Info shows the size in KB or MB, which tells you how far it has to shrink.

  2. Open the compress tool

    Open the compress tool in Safari, Chrome or Firefox and drag the PDF from Finder onto the page.

  3. Type the size you need

    Enter the limit the upload form or the mailbox gives you, in KB or MB, and press the button.

  4. Download and check

    The finished file lands in Downloads. Open it in Preview and look at one page of text and one page with a picture.

The quickest way to make a PDF smaller on a Mac

The compress tool opens in any Mac browser and does the whole job inside the tab. Drag the file from Finder onto the page, type the size you need, and press the button. It picks the method that fits each document: tidying the file structure, re-encoding photos, or redrawing scanned pages at a lower resolution. Then it reopens the result, confirms every page is there and the text still reads, and hands you the download.

Nothing is uploaded. The engine is JavaScript and WebAssembly served to the page, so the PDF is read by code running on your Mac. That makes it safe for a payslip, a contract or a medical letter, and it also means it keeps working on a train with no signal once the page has loaded.

Reduce File Size in Preview

Preview has a built-in filter. Open the PDF, choose Export from the File menu, open the Quartz Filter menu, pick Reduce File Size and save under a new name. It is fast, it is free, and it is already on every Mac.

The filter applies one fixed setting to every image in the file. It has no size box, so you cannot ask it for 500 KB, and on a photo or a scanned page it often goes further than the job needs and leaves the picture soft. Save the export under a new name, open it next to the original, and zoom in on the busiest page before you send it. If the result is softer than you want, or still too big, the browser tool gets you to an exact number instead.

Why a size target beats a slider

Most people compress a PDF because something has refused it: a job portal that takes 2 MB, a visa form that takes 200 KB, a mailbox that bounces anything over 20 MB. The number is fixed, so the useful tool is one that takes the number.

The compress tool searches for the smallest change that meets your size and stops there. A text document is usually tidied rather than redrawn, so it looks exactly as it did. A phone scan gives up the resolution nobody can see on screen. For the common limits there is a page each, such as Compress PDF to 200 KB and Compress PDF to 1 MB, with the size already filled in.

Text stays text

A PDF made from Word, Pages or a web page holds real characters. You can select them, search them, and paste them into an email. Some compressors turn every page into a photograph of itself, which shrinks the file and kills all of that.

The compress tool keeps text selectable on every page that had it. It reads the characters back from the finished file and compares them with the original before the download appears. Compress a PDF without losing quality explains how each method treats text, photos and scans.

Large files and long scans

A Mac handles big documents well, because the tab gets plenty of memory. A scan of a hundred pages straight off a multifunction printer is a normal job, and so is a brochure full of full-resolution photos. Compress a large PDF covers the files that are hundreds of megabytes.

If the PDF came off an iPhone, compress it on the phone before you AirDrop it, and save a step. The compress hub lists every guide for making a PDF smaller.

Questions people ask

Does Preview have a compress option on a Mac?
Yes. Choose Export from the File menu, then pick Reduce File Size from the Quartz Filter menu. It applies one fixed setting and has no size box, so check pictures and scans after the export.
How do I make a PDF smaller on a Mac to an exact size?
Open the compress tool in Safari, Chrome or Firefox, drop the PDF on the page and type the size, for example 500 KB. The tool picks the method and checks the result before you download it.
Is the PDF uploaded when I compress it in a Mac browser?
No. The compress tool runs inside the browser tab on your Mac. The document is read and rebuilt there, and nothing is sent to a server.
Will compressing a PDF on a Mac make the text blurry?
Not with the compress tool. Text stays as real characters, and the tool reads them back from the result before it offers the download. Photos and scanned pages are the parts that give up detail.
Where does the compressed PDF go on a Mac?
To the Downloads folder, under a name that ends in the new size. The original stays where it was, untouched.

Do it now

The tool runs in this browser. Your file never leaves the machine, and the result is checked before you download it.

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